Telephone-exchange system.



G. DEAKIN.

TELEPHONE EXCHANGE SYSTEM.

APPLfCATlON FILED AUG. P9, l9l2.

Patented Oct. 31,1916. 5 SHEETS-SHEET I- Gum/nap?- J m N G. DEAKIN. TELEPHONE EXCHANGE SYSTEM. APPLICATION man AUG. 19. 1912.

5 SHEETS-SHEET 2- 51400441913 braflfimkuv Patented 0%31, 1916.

G. DEAKIN.

TELEPHONE EXCHANGE SYSTEM. A'PPLICATION FILED AUG. 19. 1912.

5 SHEETSSHEET 3- HI" n 11M atfoameqd Patented Oct. 31, 1916.'

G. DEAK'lN. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED AUG-19,1912.

Patented Oct. 31, 1916.

BSHEETS-SHEET 4.

Wane/pus W G. DEAKIN. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED AUG. 19. I912.

Patented Oct. 31, 1916.

5 SHEETS-SHEET 5.

citizen of the United States, residing at UNITED STATES PATENT orrion.

' GERALD DEAKIN, OF SAN FRANCISCO, CALIFORNIA.

TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Patented Oct. 31, 1916.

Application filed August 19, 1912. Serial No. 715,813.

To all whom it may concern Be it known that I, GERALD DEAKIN a an Francisco, in the county of San Francisco and. State of California, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the following is a specification.

My invention relates to telephone exchange systems in which subscribers lines are interconnected by means of automatic switching apparatus, and more particularly to a combined automatic and semi-automatic private branch exchange system to be used 1n connection with such a system.

An object of my invention is to provide a private branch exchange system of the above type in which connection is made either automatically or semiautomatically according to the act of the calling subscriber.

Another object is to provide a novel arrangement of circuits and apparatus whereby the same connector switch may be operated, first to connect with an operator, and

- subsequently operated by said operator to extend the connection to the wanted subscriber.

Other improvements tending to increase the efiiciency and flexibility of such systems are hereinafter set forth in the accompanying specification and drawings. 1

In the drawings: Figure 1 is a mechanical operator or switch for connecting with local subscribers or an idle outgoing trunk. Fig. 2 is a first selector in which the incoming trunk from the private branch exchange terminates, and is situated at the main ex change. Fig. 3 is a second selector in the main exchange. Fig. 4 is a .rotary"'th1rd selector at the main exchange. Fig. 5 is a busy back circuit connected with certain sets of. contacts of the several connector switches. Fig. 6 is a trunk circuit situated at a private branch exchange and leading from contacts in the banks of connector switches of the main exchange. Fig. 7 is a connector switch in which the trunk circuit of- Fig. 6 terminates and is situated at a private branch exchange.

Throughout the following detail description and on the several figures of the drawings, similar parts are referred to by like reference characters.

Referring to Fig. 1, A indicates a subs vibers station with the usual hook H, re- *l\'}? R, transmitter T, condenser C, and ringer Q. D is a set of contact springs controlled by a calling dial adapted to open a line circuit intermittently when in operation. V and R represent subscribers line contacts which are adapted to be engaged by. the switch wipers 20 0.0 and w*, respectively. 1.7, 18, 19,20 and 21 represent side switches controlled by the private magnet M', each side switch being arranged to make successively three connections, indicated by the side switch number suflixed by the letters, a, b and c. D represents a cut-- relay L. K is a double-wound relay through which the battery 2. is bridged across the trunk conductor. The relay K controls a sluggish or slow-acting relay L through a front contact 27. The relay L in turn controls a series circuit including the sluggish relav M and the vertical magnet VM. Relay M is providedwith make before break contacts through which it controls the private magnet PM. RR is a ringing relay controlling contacts 60, 61 and 177, 178, and is adapted to be intermittently energized through an interrupter I. Contact spring 31 is adapted to make and break the contacts showing when aparticular number is called, and upon actuation energizes the relays S and H in series. These relays when energized are arranged to free the electrical cireuit ofthe switch from a circuit adapted to the establishment of local connections. as done by a connector. to a circuit adapted for the trunking of calls to other switches as done by a selector. N is a high resistance retardation coil. A supervising relay -E and 181' and the test or affords means for holding the switch busy during trunked connections. F is energized upon connection with a busy line, and actuates to connect a busy-back to the subscribers circuit. Relay I is an interrupter adapted to be connected in series with the rotary magnet RM for testing.

Referring to Fig. 2, 185 and 186 are trunk wires'multipled to contacts such as 0, 0 respectively, appearing in the banks of the switches such as S at the private branch exchange. 0 is a test or private contact in the bank of switch S (Fig. 1), and is multipled to other private contacts associated with corresponding multiple contact terminals of the trunks 185 and 186. The trunk wires 185 and 186 terminate in the main exchange in the wipers of side switches 63, 64.. Each side switch is provided with other wipers 65, 66 and is adapted to be actuated in the usual manner by the private magnet M VM is the. vertical magnet for the switch S and RM is the rotary or testing magnet for said switch. K is a double-wound repeating relay adapted to be connected in series with the calling device of substation A, and controls a slow-acting relay L. Relay L controls a series circuit including a sluggish relay M and the vertical magnet VM. Release magnet J is controlled conjointly by the off-normal contacts 67 and relays K and L. The switch S? is provided with the usual contact wipers w, w, w, adapted to engage contacts 0", 0, 0, leading to additional selector switches (Fig. 3.)

Referring to Fig. 3, the trunk wires 187 private wire 188, terminate in contacts 0", 0, 0 which appear in the bank of switch S and are multipled to similar contacts appearing in the banks of other first selectors. The switch S is also provided with wipers w, w, we, repeating relay K sluggish relays L and M, vertical magnet VM rotary magnet RM release magnet J private magnet M", and side switch wipers 70, 71, 72, 73, 74.

The rotary third selector (Fig. t), differs from the first'and second selectors in that it does not operate vertically and horizontally on one digit. One digit is required to operate it vertically, and another horizontally, after which it will rotate until a non busy trunk is selected, or until it reaches a special busy stop to be hereinafter described. It operates vertically in the same manner as the first and second selectors, after which the rotary magnet, instead of being connected to an intermittent circuit for testing, is put under the control of a repeating relay, whereby it operates to step the switch around to a predetermined position, which brings its wipersali, 11), into engagement with the terminals of the first of a set of trunks leading to a private branch exchange, and should the first trunk be busy, the rotary magnet RM will operate to step the switch around until its wipers engage an idle trunk, all in a manner as hereinafter set forth in the description of operation.

Referring to Fig. 5, R is a low-wound relay having one terminal connected to battery and the other terminal multipled to busy stop contacts such as 0 R is a relay of comparatively-high resistance hav-.

ing one terminal connected to battery and the other terminal multipled to contacts such as c appearing in the bank of the rotary third selector S. The contacts 0 0 and a grounded contact 0 constitute a set which are arranged in the bank of the rotary third selector S immediately succeeding the set of contacts belonging to the last one of a group of trunks leading to a private branch exchange, so that if all the trunks of the'set are busy, the wipers in stepping off the terminals of the last trunk will immediately engage busy stop contacts 0 0 c.

In Fig. 6, the trunks 75, 76' lead from the multiple contacts 0 and 0 in the banks of rotary third selector switches S in the main exchange and terminate in the private branch exchange, in contacts of the cut-off relay D through which they are normally connected to extensions 77, 78, which form part of a circuit of a connector switch (Fig. 7.) The cut-off relayD and relay R are controlled by the key 79. Relay R and lamp 80 are normally connected to the wire 81 through a contact of the key 79. R controls the local circuit containing a buzzer 82.

The buzzer 83 is actuated upon a closure of the key 79, and it is also controlled by a normally closed contact of D 0 is an operators control circuit including all of the apparatus indicated below the dotted line in the drawing, and is adapted to be operatively connected to the trunk wires 77 and 78 upon the actuation of relays D and R, whereby the operator is given control of the connector switch. (Fig. 7). in a manner to be hereinafter set forth in the description of operation. The circuits and apparatus shown in this figure (Fig. 6) are contained circuit with the same, along with a calling mounted in the form desk set, which con" for connecting the,

dial adapted to intermittently open the contact springs 110 and to maintain the closure of a pair of contacts 111. This cabinet is provided with a set of keys such as 79, 109, 112, etc., for each incoming or 13 trunk from the main exchange. Each trunk is also provided with signals, such as lamp 80. Relay R is energized when ground potential is placed upon conductor 81. The lamp 80, being in series with R lights whenever the latter is energized. The answering key 79 is adapted, upon actuation, to complete a series energizing circuit of relays R and D The retardation coil 99 bridges battery across the conductors 113 and 114:. Listening key 109 normally connects the operators telephone set OT to the conductors 113 and 114, and when actuated disconnects the operators telephone from the first-mentioned conductors and connects it through normally open contacts of R to the trunk conductors 77, 7 8, leading to the called substation. The listening keys 109, 112, etc., permit the operator to converse with the called instead of the calling party. It will be noted that all listening keys are wired in series so as to make it impossible to connect trunks together. In operating the operators control circuit, indicated below the-dotted line, the. contacts 111, which are maintained closed as long as the calling dialis off normal or zero position, completes the circuit of a shunting relay 107, whose function is to maintain a shunt or short circuit across the connector trunk conductors 77, 78, through the circuit interrupting springs 110. Relay 107 also controls the circuit of relay 100,-

which in turn controls the circuit of relay 184 and in conjunction with relay 106 controls the circuit of a common supervisory lamp 108. Relay 106 is a supervisory relay energized when the called subscriber answers. The relay 105 is a sluggish relay whose function is to maintain a closed circuit around the contacts of relay 100 during a series of interruptions by the calling dial springs 110, so that relay 100, which is quick acting, will be guarded against chattering during these interruptions.

Referring to Fig. 7, the connector S is provided with connecting wipers w, w, w, adapted to connect with any one of a plurality of sets of contacts 0 0 0, re-

spectively, or a special set of contacted-" the same manner as the corresponding relays of the other selector switches. Relay 86 is a "testing relay which controls the busy back signal, and the circuit of the rotarymagnet RM. Relay 88 is a special reverse relay adapted upon actuation to reverse the connections of K with the trunk conductors 77, 78, and is energized when the called subscriber answers. RR is a ringing relay which upon actuation connects trunk conductors 117, 118 through springs 89, 90 to the terminals 119, 120 of a suitable ringing generator, and is adapted to be termittently energized through an interrupter 87. Relay 97 is of high resistance, say 3300 ohms, and it is connected in series with the lower winding of K through side switch 101, and also aflords supervision by varying the current strength when the called party answers. Relay 96 is the battery supply relay for the called substation, and also controls the relay 88, and a shunting circuit 121 of the relay 97. J is a release magnet having its circuit normally open at the 03 normal contact 98. The private magnet M is controlled by the make beforebreak contact 122 of relay M and operates upon each energization to prepare the side switches 101, 102, 103, 101 105, for movement upon its subsequent deenergization.

It will be noted that the calling and called branches of the connector are separated by condensers C", C, so as to prevent the flow of direct current from one section of the circuit to the other section.

In all of the foregoing switches, the release takes place upon deenergization of the sluggish relays, L, L L L and L which close the circuits of their associated release magnets through their back contacts. The release circuits are opened at the off normal contacts when the switches resume their normal or zero positions.

The operation of my system is as follows: Assuming that the private exchange subscriber at station A (Fig. 1), desires to make a complete automatic connection with a subscriber in some other private branch exchange, without the aid or knowledge of an operator, he removes the receiver from the switchhook which closes a circuit through his telephone set from battery 2 (Fig. 1), through one winding of K, 37, 60, T25, T telephone set at substation A, including contacts D of a calling dial, conductor T, 4, windings of meter G, 13., 12, the other winding of K, to ground. This circuit does not operate meter G, as it is polarized so as not to operate on this circuit; however, the relay K is energized on this circuit, and upon actuation .completes the energizing circuit of relay L from ground at 1 through 28, 27, L, to battery 2. When the calling dial is operated, the line circuit is momentarily interrupted at contact sprin s D'a number of times corresponding to the first.)

digit of the number of the wanted substation, and at each interruption the relay K is disengaged. The duration of these interruptions is so adj usted-as to permit relay K to respond to them, but not the sluggish relays L and M. Each time relay K is deenergized, the relay M and vertical magnet VM are energized by current over the 'following path: from ground at 1 through 28, 29, 25, 24, M, VM, 17, 17, to' battery at 2. At each actuation of the vertical magnet the switch wipers are stepped up one row or unit. Relay M, being sluggish, remains energized or actuated during the intermittent actuations of the vertical magnet. Relay M, attracting its armature, energizes private magnet M by current from ground at 1, through 31, 68, 43, 12, M, to battery at 2. Following the cessation of the series of interruptions is a prolonged closure of the line circuit which holds relays K and L energized fora suitable length of time to permit sluggish'relay M to retract its armature, its circuit being open between 28 and 29. When relay M retracts its armature it opens the circuit of private gnagnet PM which upon deenergization allows the side switch arms to step into the second position, the arms 17, 18, 19, 20 and 21 breaking contacts with 17*, 18 19*, 20 and 21", and engaging contacts 17", 18 19", 20 and 21", respectively. It is to be noted here that the first digit of all calls out of the private branch exchange is 0, i. e.,the call num ber of all outgoing calls is preceded by the digit 0, so that in making such calls the mechanical operator (Fig. 1), is always operated to step its wiper up to the tenth level or row of contacts. Upon the arrival of the switch wipers at the tenth level, the 011'- normal or foot step spring 31 breaks contact with 68 and makes contact with 32 and 33. This energizes relays S and H in series,

in the following circuit: ground at 1 through contact 33, S, H, to battery at 2. The windtings of relays K and Q are now disconhected from the calling line by the opening of contact between 37 and- 60,. 50 and 51, 12 and-13, and 9 and 10. The closure of contacts 51-69 connects relay E in series with one side of the calling line. By the closure of contacts 1011, wiper w is placed indirect metallic contact with the calling line.- At the end of the first series of interruptions, which stepped the switch up to the tenth row, sluggish relay L resumed its normal position, which deenergized private magnet M, and which in turn permitted side switch wipers 17 18, etc., to step into their second or test position.

When the contact is brokenbetween Band 7 and made between 7 and 8, upon the actuation of H, thus removingfthe rotary magnet RM from the control of relay K and ing circuit of private placing it in series with interrupter I, the

magnet RM may be, traced as follows: fromground at 1, through 16, I 8, 7, RM, 17*,

'17, to battery at 2. The switch is rotated b the intermittent actuations of the rotary magnet. RM and is prevented from releasing during this stepping by the holding up of the private magnet M in a circuit from battery 2, through M, 49, 48, 20", 2 0, 'w

\ to ground by way of private contact 0 if When the v 4 its associated trunk Y is busy. trunk is busy, connection to ground may be traced from contact 0 through wiper w to another mechanical operator, such as S,

connected therewith for the time being, through side switch arm 20 to ground through 20. In this way the private magnet is maintained energized as long as the private wiper w passes over busy contacts. The moment, however, an ungrou'ndedcontact or non-busy trunk is selected, the circuit of M is opened and the side switches are stepped to their third or 0 position. The wipers e0 10 w now engage contacts c (2*, respectively, of the trunk 185186, terminating in the side switch arms 63, 6i of' a first selector in the main exchange. The repeating relay K is now energized in series with the contacts D of a calling dial at substation A in the following circuit: from ground at 1 (Fig. 2), through lower winding of K, 64*, 64, 186, c, to, 19, 19, 178, 67, 51, 69, E, T 5, T telephone apparatus at substation A, D, T, 4, G, 11, 10, w", 0 (Fig. 2), 185, 63, 63, upper winding of K, to battery 2. The actuation of K energizes the sluggish relay L. The subscriberat substation A now operates his calling dial a second time, and the momentary interruptions at contact springs D cause relay K to drop back intermittently and in so doing, closes a. circuit from ground through its armature and the armature of L, and thence through sluggish relay M vertical magnet VM, 65, 65, to battery. Thus at each release of the armature of K, the vertical magnet is actuated to step the switch up one row for each interruption given by the calling dial. The sluggish relay M however, remains continuously energized until the cessation of said interruptions.

The actuation of M completes the energizmagnet M thus preparing the side switch to step its wiper arms 63, 64, 65, and 66 into the second position upon its. subsequent denrgization. The prolonged energization of K, following the series of interruptions, permits sluggish relay M to retract its armature which deenergizes private magnet M which permits the side switch to step to the second position. The rotary magnet RM is now. intermittently energized in a circuit from battery 2 through side switch wipers 65, 65

RM, back contact of armature 122, td

ground. It should be noted that the rotary magnet carries an arm, which when the rotary magnet first operates, acts mechanically upon the armature of the private magnet M to cause it to perform its function of preparing the side. switch for its second step, the same as if it were energized. Should the first trunk be busy, at ground potential will be found upon the private contact 0 (Fig. 3), and it is transmitted through wiper 4,0 private wiper 66, contact 66", M to battery at 2. The groupd on 0 is obtained from the next switch through the closed upper contact of relay L thence through side switch 7 3 to ground' or in case this switch has been operated, through side switch 73, in its third position through side switch 74; in its third position, through wiper. w to a ground from the next switch, after the manner just described. As soon as the switch wipers engage a set of contacts leading to a non-busy trunk, the opening of the circuit through the private magnet allows the side switch to escape into the third position, which removes relay K from connection with the trunk conductors 185-186, and connects said conductors straight through to the second selector (Fig. 3): Relay K (Fig. 3), is now energized in series with the interrupter springs D at the substation A, through side switch wipers 70, 71, and g contacts and 71, respectively. The actuation of K energizes L which holds botli switchesb-usv through its armature. and the side switch wiper 73. The subscriber at sub-station A. now operates his calling dial to send in the third digit: The operation of the second selector is the same as the first selector, and for this reason not be further mentioned. Aft the third digit has been called, the second selector then completes the connection straight through to the rotary third selector (Fig. at), and relay L of this switch S holds all three switches busy.

The rotary third selector diflfers from'the first and second selectors in that it does not operate vertically and horizontally on one digit. One digit is required to operate it vertically and another horizontally, after which it will rotate until its Wipers engage the contacts of a non-busy trunk of the group corresponding to the last digit,.and which lead to the private/branch exchange in which the wanted substation is situated.

When the side switch steps into the second position, the wiper 95 disconnects the vertical magnet VM at 95, and connects rotary magnet RM at 95 -in the same circuit by which the vertical magnet VM was energized. The circuit of RM may be traced from ground, throu h armature otK armature of L M, R 95", 95, to battery 2.

selected and leading to the called private 7o branch exchange. In Fig. 5 the terminals of tiwo such groups of trunks are shown, each group consisting of two trunks, the associated terminals of which are arranged successively in' the same row or level, each 75 group of such sets of terminals being immediately succeeded by a set of contacts such as 0 0 and 0 which are what I term the busy stop. Should the first trunk be busy, ground potential will be found upon the private contact 0 which passes through wiper w", 92, 92 normally closed contact of M conductor 123, M tobattery 2, and maintains the private magnet M energized while the wipers of the switch S are passing over busy contacts. The ground connection to the contact 0 of the busy trunk maybe traced from ground, through side switch wiper 91, to another switch, such as S occupying a trunk, and through the circuits of that switch by way of conductor 124, upper armature of L conductor 125,

low wound relay 85, contact 92, 92, w", multiple of contact 0 to 0 The moment a non-busy trunk is selected, the private ,.95

magnet is denergized, thus allowing the side switches to step into their third 'position and thereby connect the calling circuit straight through to the trunk 7 576 by way of wipers c0 and w and contacts 0 and 0 respectively. Should all the private branch exchange'trunks be busy, the wipers of the selector; S will have rotated to the busy stop i-contacts 0 0 0 (Fig. 5).

It will be noted that the contact 0 is connected to battery 2 through relay R and therefore when the private wiper w" engages this contact, the private magnet M will be deenergized as it is also connected to battery. Denergization of M causes the side switch to; step to the third position, the

' switch being held busy in this position by relay 84 which is energized in series with the high resistance relay R connected to battery and the ground connection at 0 which latter are bridged across the trunk through wipers w and w. The relay 84- holds the switch S busy by virtue of the ground connection through armature 126 to relay L which being energized thereby connects ground to wire 127, by way of side switch wipers 91 and conductor 124, which connects directly to contact a and, by way of wire 125, 85, 92,and92, to wiper w". Re-

lay 85 is now energized inthe following cir- 1% cuit: battery 2 (Fig. 5), through low resistance relay R 0 w, and thence to ground through 85, as above traced, Relay 85 upon actuation locks up through its front contact and wire 123 in series with private magnet M and clears the private wiper w by opening its back contact, so that should other switches be thrownto the busy stop, they will be allowed to engage said contact.

The relay R", upon actuation, connectsa suitable busy tone test or busy back circuit, as indicated, to the trunk conductor 128 by way of contact 0 and wiper 10 The calling subscriber at substation A receiving' the busy signal, hangs uphis recei er, which opens the line circuit at the switch hook contacts and as the energizing circuit of relay 84 is included in series in this circuit, this relay is del-Znergized and in turn denergizes L The release of the armatures of relay K and L completes the energizing circuit of release magnet J as follows: battery 2, through off-normal contacts 130, J lower armature of L armature of K to ground. The actuation of the release magnet causes the release of S, which upon assumingitsnormal position opens the off-normal contacts 130. The retraction of relay L also'removes the ground connection from wire 127 and contacts 0 which opens the holding circuit of relay L (Fig. 3), and L retracting its armatures energizes the release magnet J restoring the switch S to normal, likewise S is restored in the same manner as that described for the restoration to normal of switch S".

The switch S (Fig. 1), was restored upon the permanent opening of the line circuit at the switch hook A, as follows: The relay K being energized in series with the line circuit is deenergized upon interruption of the same, and retracting the armature opens the holding circuit 131 of relay L which in turn energizes release magnet J, resto g the switch to normal in a manner similar t that described for the other switches.

Assuming that the switch 3* (Fig; 4),

upon connection with the contacts 0 0 0 finds the trunk 75- 7 6 (Fig. 6) idle, the circuit traced from battery through private magnet M to ground through wiper w,

will beopened and M -'deenergized, which allows the side switch to step itself into the third or 0 position. The contact springs of the calling device D at station A (Fig. 1) i are now connected in series with the energizing circuit of repeating relay K (Fig. 7

The circuit of K may be traced from battery 2 through upper winding of K armature 134: of relay 88, trunk conductor 77, into Fig. 6, armature 132, 75, 0 w, 128, 94, 94, 0 over the trunk circuit of the other switches through contacts of calling device D and telephone apparatus at A, and back to contact 0 as before described, and thence through 93, 93, 129, w, 0 (Fig. 8), 76, 133, 78, into Fig. 7, 135, lower winding of K to' ground through side switch arm 101. The completion of this circuit ener- O gizes relay K and gives the calling subscriber control of the'honnector switch S'. 7

The operation of the connector is similar to that of the rotary selector (Fig. 4). The first set of impulses affecting the switch cause it to step vertically'and the second set cause it to rotate horizontally and engage the terminals of the called line. At the end of the second set of impulses the wipers w", w and w engage the contacts 0", c and 0 respectively, which connect with the terminal apparatus of the called subscriber in the same manner in which the contacts P,V R connect with the terminal apparatus 0 substation A (Fig. 1). At this juncture, the side switch arms 101, 102, 103, 104 and 105 are in their second or 5 position, and should the called line be busy, the usual ground potential will exist at the private contact 0", so that when the sluggish relay M retracts its armature, its back contact making before its front contact breaks, the private magnet M is maintained energized by the following circuit: ground through battery 2, M 122, relay 86, back contact of 86, 103, 103, w and to ground through contact 0". This circuit energizes the relay 86, which locks itself to ground through a front contact 138 and wire 137. The actu q e a I I u hanging up 1118 receiver, opens his lme circuit which denergizes relay K. .The deenergization of K opens the circuit of L which, upon deenergization, completes the release circuit from ground, through the back contact of K back contact of L, J,

and through oil-normal contact springs 98" to battery 2. The actuation of the release magnet J restores the switch S and its associated circuits and apparatus to normal,

as shown in the drawing. The preceding switches are released and restored to normal in the same manner as before described. -The busy test otential on the test'contact c" of the called inc is established in either.

of two ways, as follows: If the called line is connected with by another connector, such at S, at the time of the connection just described, the test potential on contact c may be traced from groundthrough side switch contact 103, side switch arm 103, and wiper w", of the previously connected switch, and thence through the multiple of 0, to contact c". If the called subscriber is calling at the time of connection, the test potential I at contact a" is established in the same manner as indicated in Fig. 1, where it is shown that after the side switch arm has moved into either its 6 or a position, the .test contact P, which corresponds to contact 0" of the called subscribers line, is connected to ground.

Assuming that the called line is not busy at the time of connection, the private magnet M is denergized upon theretraction of armature 122, and allows the'side switch 1 arm to step into the third or c'position-'.Qi

The ringing relay RR* s now intermittently in the following circuit: battei'y'2 through sw itch arm 105, contact 105, back contact of relay 88, RR to ground through interrupter 87. The ringing relay RR controls the armatures 89 and 90 in such manner that upon each energization it openscontact between 89-140 and 90-141, and closes contact between 89-119 and 90-120. Then the ringing generator Gr. is intermittently connected across the trunk 117-118 which connects through to the called substation. When the called subscriber answers he closes his line circuit in the "usual manner and, at the next nonringi- 'ig interval, relay 96 is energized in series with the calling line in the following circuitf'battery'2 through through 103.

now shunted out by the side switch arm 105, 105, 142, 96, 143, 144, 145, 140, 89, 117, out over the line through the called substation apparatus and back to trunk conductor 118- by way of wipers (r -Q0 and into side switch wiper 104,

and thence through 90, 141, 146, 96 to groundat 103. The actuation of relay 96 completes the energizing circuit of relay 88 which circuit may be traced from battery 2 through armature 147, 88, to ground Relay 88, attracting its armature, opens the circuit of the ringing relay BB and locks itself to battery at armature 148, and reverses the connections of the battery supply relay line and thus reverses the circuit, following through the winding of meter G (Fig. 1), and registering the call. The locking circuit of 88 may be traced from battery 2 through side switch arm 105, 105, front ,contact of armature 148, 88 to ground through 103. The high resistance relay 97 which was cut in series with the grounded side of relay K when the side switch arm 101 stepped into its third or a position, is closure of the lower contact of relay 96 which connects the wire 121 to ground through contact -103, thus supplying current to the calling line throughrelay K only.

Talking conductors 77-78 are separated from the conductors 115-116 by condensers 7 and C respectively, and the called substation is supplied with current through the windings of relay 96. The calling and called subscribers are now connected for conversation over the circuit indicated in heavy lines." At the end of the conversation, the calling subscriber upon hanging up his receiver restores the switch in a manner as before described.

It will be seen complete connection as above that the operation for a described is K with the calling that the operator has no means of listening in, or of connecting with any of the circuits involved. It is also to be understood that such a connection may be made with 'I any of the substations whose linesv terminate in the contact bank of the connector switch S Fig. 7, providing that the calling subscriber has knowledge of the requisite num-.

ber. However, in such systems it is often necessary to have a general information station', and in the management of most private branch exchange systems it is desirable, in the interests of privacy and economy, to have the call numbers of certain substations withheld fromthe public, and to have all general or miscellaneous calls come in to an information operator whose duty it is to delegate them to the appropriate substations. The receiving cabinet, Fig. 6, is provided for such purposes and is brought into operation whenever the number sent in is such as will land the wiper. of the connector switch, Fig. 7, on the contacts 0 0 and 0.

Assuming that the general call number is sent in, the wipers w", w, and w, will be stepped into engagementiwith the contacts 0, c and 0 respectively, and the side switch arms 101, 102, etc., will assume their third or c'positions, all in a manner as before described. From this juncturethe operation continues as follows: Upon the engagement of side switch arm 103 with a contact 103, the series circuit of call lamp 80 and relay-R (Fig. 6), is completed and may be traced from ground at contact 103 through 103, w", 0 81, normally' closed -fcontact of answering key? 9, lamp 80, relay R 'through battery 2 to ground. Actuation of R completes the circuit of call buzzer 82 to battery 2 through a front contact, the other terminal of the buzzer being normally connected to ground through switch' hook contacts 149 of'the operators telephone set OT. The operator perceiving the signal 80 or 82, operates the answering key 79,, which energizes relays R and D in series, the circuit being traced as follows: battery 2 through R, D contact of key 7 9, wire 81 into Fig. 7, contact 0 w, to ground at 103. This circuit is locked to ground from wire 81 through a front contact of armature 1500f relay D vtures 132-133 of D opens the connector circuit, Fig. 7, allowing the connector S to release, and connects the calling end trunk, 7 5-7 6, to the retardation coil 99, there by holding the preceding switches busy. The calling'end of the trunk is also connect- The attraction of armaof the are ed through a listening key 109 to the operanormally open contacts 153 and 154, re

spectively, of the listening key 109, and to Wires 155 and 156, respectively, leading to the operators calling device 110.

Vhen the operator raises her receiver the switch hook operates to open the circuit of the buzzer signal and connect the operators talking circuit across the conductors 157 and. 158, leading to the calling end of the trunk through normally tening key 109. Upon ascertaining the number wanted, the operator operates her calling device to send in two sets of interruptions or impulses corresponding to the digits of the wanted branch. The moment the operators calling device is moved 011 normal, the shunt springs 11]. make contact and close the energizing circuit of shunting relay 107. Belay 107 completes a shunt across the connector trunk, through the contact springs 110 of the calling device, energizing the repeating relay K of the connector 8, Fig. 7. This circuit may be traced from battery 2 (Fig. 7) through upper winding of K*, 134, 77 into Fig. 6, 152, 155, 110, 159, 160, 162, 163, 156, 151, 78 into Fig. 7, 135, lower winding of K. side switch arm 101, and to ground through contact 101*. Relay 107, upon actuation, also completes the energizing circuit of relay 100 by the closure of contact 161, and relay 100 in turn energizes sluggish relay 184 through its front contact 164. Relay 105 completes a short circuit around contact 165 of relay 100 to guard the circuit through relay 100 from interruption in case of the opening of contact 165, before the called party answers. The circuit traced through relay K same, which in relay L The two sets of intll uptions produced by the operators calling device now operate to step the connector switch wipers into engagement with the contacts leading to the wanted substation in the same manner as before described. However, if the called substation is busy the busy signal will he received by the operator as the connector trunk 77-7 8 will now be connected to her telephone set whenevershe actuates the listening key 109 which connects the trunk 7778 through conductors 153-454 to conductors 157158. The operator receiving this signal, notifies the calling party and releases the answering key 79 which opens the circuit of relays D and It. The retraction of armatures 132-133 ct ID diseonnects'the connector trunk 777 8 from the operators control circuit, and connects it to the trunk: 76 so that the calling subscriber will now receive the busy signal until he hangs up his receiver, which restores all the switches.

Assuming that the called substation is not busy, the side switch arms 101, 102, etc, will step into the third or a closed contacts of the lis-' (Fig. 7), energizes the turn energizes sluggish Dosition, which holds the circuits busy and automatically rings the connected substation all in a manner as before described.

When the side switch arm 101 moves into the third or 0 position, the lower winding of K is connected to ground through a high resistance relay 97 by way of contact 101, and the circuit then established is as follows: battery 2 through K, 134, 77, into Fig. 6,152, 155, 1.10, 159, 165, 100, 106, 156,

K*, 101, 101 to 151, 78 into Fig. 7, 135, ground through 97. Relay 106 will not pull up through this high resistance. Whenthe called party answers, the relay 96 becomes energized which in turn energizes 88, all in a manner as before described, and the relay 97 is shunted to ground through wire 121, lower contact of 96 to ground through 103 and 103. The increase of current due to the shunting out of relay 97, energizes relay 106 which completes the circuit of the answering lamp 108, notifying the operator that the called party has answered. The operator perceiving this signal, releases the answering key 79, which denergizes relays D and R", connecting the trunks 7576,

and 77-78, and removing the 'operators control circuit from the-circuits of the com nected subscribers; as before described. The talking circuit thus-established and the manner of release are also the same as previously described.

A feature not previously described is the back release circuit. "Relay 96 when operated in addition to energizing 88 also ener-- gizes sluggish relay 170. When relay 96 is dee'nergized by the wanted subscriber hanging up, it closes a circuit from ground through 103, 103, 172, 171, which remains closed on account of 170 beingsluggish, J, 98, to battery 2. The release magnet J thus energized, releases the switch 8 but not the remainder of the connection. This back release feature permits a subscriber to call successively, ing required to hang up each time and call the whole number over again. He is merely required to call the two digits representing the next station wante It is to be understood that in addition to the set of contactsc c and c, Fig. 2, appearing in the tenth row in the contact bank of switch S, Fig. 1, there. are several other rows of sets of contacts, not shown, such as the set V, P and R which constitute the terminals of other subscribers lines in the same private branch exchange with subscriber A. Whenthe subscriber A desires to communicate with some other in the same private branch exchange he removes his receiver and operates his calling dial D to cause the switch S to step its wipers up to the particular row stituting the terminals of the'wanted line, inthe same manner as beforedescribed except that the switch wipers are not stgpped a number of stations without-be.-

subscriber I of contacts conup as far as the tenth row so the foot step spring 31- is not actuated to complete the circuit of relays H and J. Thus, whenthe side switch arms 17, 18, etc., of the switch S assume their second or b position after the first set of impulses and the denergization of the private magnet, the rotary magnet RM, instead of becoming connected with the interrupter I through the normally open contact 8 of relay H, becomes connected in series with the sluggish relay M over the following circuit: battery 2, side switch arm 17, 17 RM, 7,6, 53, 52, M, 24, 25, 29, 28 to ground 1 and back to battery 2. The calling subscriber again operates his calling dial to cause his line circuit to be interrupted a number of times corresponding to thesecond digit of the number of the wanted subscriber. Each interruption of,the'line circuit causes an energization of the rotary magnet BM, in series with the sluggish relay M, to step the wipers of the switch around one step, in the same manner that the vertical magnet VM was energized to step the switch wipers up to the row. At the last energization of the rotary magnet RM, the switch wipers 10 10 and w are stepped onto the particular set of contacts constituting the terminals of the wanted line, after which the sluggish relay M again denergizes retracting its armature and opening the circuit of the private magnet PM at 43 and connecting it through contact 42 to wire 41. If the called subscribers line is busy its test contact corresponding to contact P will be grounded and the pri-- vate magnet will be included in the following circuit: battery 2, private magnet PM, 42, 41, relay F, 55, 56, 20 20, 'w grounded test contact of busy called subscriber, through ground and back to battery. This circuit energizes relay F which locks the circuit through contact 46, 22, 23 and through ground to battery. The private magnet remaining energized prevents the side switch arms from stepping to the third or 0 position while the attraction of armature 57 of relay F connects a busy back circuit through wire 182, 57, 48, 19 19, 178, and 67 to the sleeve side of the calling subscribers line. The calling subscriber hearing the busy signal hangs up his receiver which causes the switch to restore in a manner before described.

If the called subscriber 1s not busy, the

, private magnet becomes deenergized upon the opening of its clrcuit at contact 43 of upon the calling subscribers trunk becomes.

connected with the terminals of the called subscribers line via the circuit indicated in heavy lines. A circuit for the ringing relay BB is then' completed. as follows battery 2, 17, 17, RR, 45, I, through ground and back to battery. The relay RR is intermit-- tently energized in this circuit, each time attracting its armatures 61 and 178 and completing a ringing circuit for the called subscriber as follows: ringing generator Y., 60,

61, 9, 10, 10 to called subscribers statlon,

.back over wiper w, 19, 19, 178, 177 to genorator Y. At the next non-ringing interval after the called subscriber removes his rece ver, completing hlS line circuit in the. usual manner, relay Q becomes energized 1n Having thus described the invention, what is claimed as new is:

1. A telephone exchange system in which subscribers lines are interconnected by means of automatic switches, ,a connector switch adapted to connect its circuit with any one of a plurality of sets of contacts, controlling means for said switch, an auxiliary directive control for said switch, and means operable upon the connection of the connector switch with a predetermined set of the contacts to render said switch operative by the auxiliary control, whereby the connector switch may be again actuated to connect with any one of said sets of contacts.

2. A telephone exchange system in which subscribers lines are interconnected by means of automatic switches, a connector switch adapted to connect its ci uit with any oneof a plurality of Sets of contacts, subscribers controlling means for said switch, an auxiliary directive control for said switch, and means operable upon the connection of the' connector switch with a predetermined. set of the contacts to render said switch operative by the auxiliary control, whereby the connector switch may be again actuated to connect with any predetermined one of said sets of contacts.

3. A telephone exchange system in which subscribers lines are interconnected by means of automatic switches, a connector switch adapted to connect its circuit with any one of'-a plurality of sets of. contacts, subscribers controlling means for said switch, an operators control for said switch, and means operable upon the connection of the connector switch with a predetermined set of the contacts to render said switch optacts.

4:. A telephone exchange system in which subscribers lines are interconnected by means of automatic switches, a connector switch adapted to connect its circuit with any one of a plurality of sets of contacts, each set of contacts constituting terminals of subscribers lines, controlling means for said switch, an auxiliary control for said .switch, and means operable upon the connection of the connector switch with a predetermined set of the contacts to render said switch operative by the auxiliary control, whereby the connector switch may be again actuated to connect with any one of said sets of contacts.

5. A telephone exchange system in which subscribers lines are interconnected by means of automatic switches, a connector switch adapted to connect its circuit with any one of a plurality of sets of contacts, controlling means for said switch, an auxiliary control for said switch, means operable upon the connection of the connector switch with apredetermined set of the contacts to render said switch operative by the auxiliary control or not, according to the desire of the calling subscriber, whereby the connector switch may be again actuated to connect with any one of saidsets of contacts. r

6. A telephone exchange system in which subscribers lines are interconnected by means of automatic switches, a main exchange, an intercommunicating private branch exchange associated therewith, means whereby subscribers in said private branch exchange may automatically connect either with other subscribers of the same exchange, or with the main exchange, trunks leading from the main exchange to connector switches at said private branch exchange, the latter being adapted to connect their respective trunks with any one of a plurality of sets of contacts, controlling means for said connector switches, auxiliary directive controlling means for the connector switches, and means operable upon the connection of of the connector switches with a predetermined set of the contacts to render said switches operative by the auxiliary control whereby a connector switch may be again actuated to connect with any one of said sets of contacts.

7. A telephone exchange system in whic subscribers lines are "interconnected by means of automatic switches, aimain exchange, an intercommunicat ing private branch exchange associated therewithmeans whereby subscribers in said private branch 55 exchange may automatically connect either with other subscribers of the same exchange, or with the main exchange, trunks leading from the main exchange to connector switches at said private branch exchange, the latter being adapted to connect their respective trunks with any one of a plurality exchange may automatically connect either with other subscribers of the same exchange, or with the main exchange, trunks leading from the main exchange to connector switches at said private branch exchange, the latter being adapted to connect their respective trunks with any one of a plurality of sets of contacts, an opcrators auxiliary controlling means for the connector switches, and subscribers means operable upon the connection of the connector switches with a predetermined set of the contacts to render said switches operative by the auxiliary control, whereby a connector switch may be again actuated to connect with any one v of said 'sets of contacts.

9. Atelephone exchange system in which subscribers lines are interconnected by.

means of automatic switches, a connector switch adapted to connect its circuit with any one of a plurality of sets of contacts, controlling means for said switch, an auxiliary control for said switch, and means operable upon the connection of the connector switch with a predetermined set of the contacts to render said switch operative by the auxiliary control and to disconnect the switch from the first-mentioned controlling means.

10. A telephone exchange system in which subscribers lines are interconnected by means of automatic switches, a connector switch adapted to connect its circuit with any one of a plurality of sets of contacts, controlling means for said switch, an auxiliary control for said switch, and means operable upon the connection of the connector switch with a predetermined set of the contacts to render said switch operative by the auxiliary control and to simultaneously disconnect the switch from the firstmentioned controlling means.

11. A telephone exchange system in which subscribers lines are interconnected by means of automatic switches, a connector switch adapted to connect its circuit with any one of a plurality of sets of contacts, controlling means for said switch, an auxiliary control for said switch, and means operable upon the connection of the connector switch with a predetermined set of the contacts to render said switch operative by the auxiliary control and to disconnect the switch from the first-mentioned controlling means and to subsequently disable the auxiliary control.

12. A telephone exchange system in which subscribers lines are interconnected by means of automatic switches, a connector switch ada ted to connect its circuit with any one of a plurality of sets of'contacts, controlling means for said switch, an auxiliary control for said switch, and means operable upon the connection of the connector switch with a predetermined set of the contacts to render said switch operative by the auxiliary control and to simultaneously disconnect the switch from the first-mere tioned controlling means and to subsequently disable the auxiliary control.

13, A telephone exchange system in which subscribers lines are interconnected by means of automatic switches, a connector switch-adapted to connect its circuit with anyone of a plurality ofsets of contacts, controllin means normally connected with said switc h, an auxiliary control for said switch, and means maintaining normal con trol and operable upon connection of the connector switch with a predetermined set of contacts to render said switch operative by the auxiliary control to disconnect the switch from the first-mentioned controlling means, and to subsequently disable the auxiliary control whereby the normal control is reestablished.

14. A telephone exchange system in which subscribers lines are interconnected by means of automatic switches, a connector switch adapted to connect its circuit with any one of a plurality of sets of contacts, controlling means normally connected with said switch, an auxiliary control for said switch, and means maintaining normal control and operable upon connection of the connector switch with a predetermined set of contacts to render said switch operative by the auxiliary control to disconnect the switch from the first-mentioned controlling means, and to subsequently disable the auxiliary control, the last-mentioned means including an instrumentality whereby a disabling of the auxiliary control is manu- 0L ally accomplished;

subscribers lines are interconnected by means of automatic switches, a connector switch adapted to connect its circuit with any one of a plurality of sets of contacts, subscribers controlling means normally connected with said switch, an operators auxiliary control for said switch, and means maintaining normal control and operable upon connection of the connector switch with a predetermined set of contacts to render said switch operative by the operators auxiliary control to disconnect the switch from the first-mentioned controlling means, and to subsequently disable the operators auxiliarycontrol whereby the normal control is reestablished.

17. A telephone exchange system in which subscribers lines are interconnected by means of automatic switches at a main exchange, an intercommunitrating private branch exchange system associated therewith, a connector switch included in the latter system, iii-coming trunks leadingfrom the private branch exchange to the main exchange, a receiver cabinet having an operators equipment, out-going trunks leading from the main exchange to the private branch exchange and passing through the receiver cabinet, and means in the receiver cabinet for establishing control of said connector switch by said operators equipment.

18. A telephone exchange system in which switch, operators controlling means for.

said switch, a signal device associated with said operators controlling means, and means operable upon the connection of the connector switch with a predetermined set of contacts to actuate said signal device whereby the operator is notified of the connection.

19. A telephone exchange system in which subscribers lines are interconnected by means of automatic switches, a connector switch adapted, to connect its circuit with any one of a plurality of sets of contacts, subscribers controlling means for said switch, an operators control for said switch, a signal device associated with said operators control, and means operable upon the connection of the connector switch with a predetermined set of contacts to actuate said signal device and render said switch operative by the operators control, whereby the operator is notified of the establishment of her control and is enabled to directively control the switch to effect connection with any one of said sets of contacts.

In testimony whereof I afiix my signature in presence of two witnesses.

GERALD DEAKIN.

Witnesses:

PAULINE J. GLAUCH, CHAS H. Doason. 

